<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <title>Title</title>
</head>
<body>
<input type="button" value="按钮" onclick="sendMessage()" />
</body>

<script src="websocket.js?sdf=2"></script>
<script src="index.js?sdf=2"></script>
</html>